Lowell Observatory

Lowell Observatory is a privately operated, nonprofit astronomical research and education center in Flagstaff, Arizona. Founded in 1894 by Percival Lowell, it is one of the oldest observatories in the United States and is celebrated as the site of major discoveries such as Pluto’s detection in 1930. Today, it remains a leader in planetary and stellar research and public outreach.

Key facts

Founded: 1894
Founder: Percival Lowell
Location: 1400 West Mars Hill Road, Flagstaff, Arizona, USA
Status: 501(c)(3) nonprofit research organization
Famed discovery: Pluto, by Clyde Tombaugh (1930)

History and mission

Established to study Mars and the solar system, Lowell Observatory quickly became a hub for groundbreaking astronomical work. Under Lowell’s leadership and that of later directors, it advanced the study of planetary surfaces and interstellar phenomena. Its mission now encompasses both scientific research and education, aiming to connect people to the universe through discovery and outreach.

Research and discoveries

The observatory’s scientists have achieved numerous milestones, including Vesto Melvin Slipher’s first detection of the expanding universe in 1912 and Tombaugh’s discovery of Pluto. Modern research spans solar physics, planetary science, star formation, and galaxy evolution. The facility’s flagship instrument, the Lowell Discovery Telescope, is among the most versatile ground-based telescopes in the world.

Public engagement and facilities

Lowell Observatory welcomes more than 100,000 visitors annually to its Mars Hill campus. Its public programs include telescope viewing, educational exhibits, and the new Marley Foundation Astronomy Discovery Center, which features an open-air planetarium leveraging Flagstaff’s dark skies. The observatory also operates the Giovale Open Deck Observatory for hands-on stargazing.

Recognition and impact

Designated a National Historic Landmark in 1965 and named an Arizona Treasure in 2005, Lowell has been integral to Flagstaff’s identity as the world’s first International Dark Sky City. In 2025, Time magazine listed it among the World’s 100 Greatest Places, highlighting its blend of cutting-edge research and immersive public experience.